Thickener and washer



Dec. 25, 1962 Filed Aug. 11, 1960 E. V. KEMP ETAL THICKENER AND WASHE 2Sheets-Sheet l INgl/Z/gORS K $735244 H. J E BY flzaferJ KOTA A/ Dec. 25,1962 E. v. KEMP ETAL 3,070,005

THICKENER AND WASHER Filed Aug. 11, 1960 2 Sheets-Sheet, 2

INVENTORS EOWIIV M KFMP w/u/fl/w IX (JO/P019 BY 191867970. aar/r/A/rmwmm 3,070,005 THECKENER AND WASHER Edwin V. Kemp, William H. Jordan,and Albert J. Botkin, Springfield, Ohio, assignors to The Bauer Bros.(30., Springfield, Ulric, a corporation of Ohio Filed Aug. 11, 1960,Ser. No. 48,927 4 Claims. (ill. 100-446) This invention relates to theart of processing wet bulk material, for example a low density fibrouspulp, and particularly to equipment supplying such material to refiningor like means under conditions expressing excess fluids.

The object of the invention is to simplify the construction as well asthe means and mode of operation of thickeners and washers, whereby suchequipment may not only be economically manufactured, but will be moreefficient and satisfactory in use, adaptable to a wide variety ofapplications, and be unlikely to get out of order.

A further object of the invention is to introduce in thickening ordensity increasing equipment of the kind described a principle ofpressure feed whereby the pulp or fibrous solids are supplied underpressure to subsequently encountered process equipment.

Another object of the invention is to utilize a principle of controlledback pressure in a thickening device as described whereby to conform tothe use of materials of diiferent initial density and to vary the amountof compression applied to the bulk material to regulate the amount offluids extracted.

A further object of the invention is to present a generally new feederfor low density materials combining aconcept of force feeding with thatof controlled dewatering or thickening ofthe material.

Still another object of the invention is specifically to improvethickening devices as described through the use of means to obtain asubstantially uniform application of pressure to the material being fed,despite losses of fluid therefrom, as well as to provide for thecreation of pressure zones along the length of the feeding apparatus.

A further object of the invention is to provide a thickener and washerpossessing the advantageous structural features, the inherentmeritorious characteristics and the mode of operation herein mentioned.

With the above and other incidental objects in view as will more fullyappear in the specification, the invention intended to be protected byLetters Patent consists of the features of construction, the parts andcombinations thereof, and the mode of operation as hereinafter describedor illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing wherein is shown one but obviouslynot necessarily the only form of embodiment of the invention,

FIG. 1 is a view in side elevation of pressure feeding apparatus inaccordance with an illustrated embodiment of the invention;

FIG. 2 is a view in end elevation of the apparatus of FIG. 1; and

FIG. 3 is a top view of the apparatus of FIG. 1, the feed mechanismbeing shown in longitudinal section.

Like parts are indicated by similar characters of reference throughoutthe several views.

Referring to the drawings, in its illustrative embodi ment the inventionis comprised in apparatus for thickening pulp material in the course ofits movement in liquid suspension to refiners or like pulp treatingequipment. In the working of pulp it frequently becomes necessary tochange the consistency of the pulp-liquid mixture. Screening andcleaning of the pulp usually is carried out with the pulp at a very lowpercentage of solids or at what may be considered a low density. After3,070,005 Patented Dec. 25, 1962 cleaning and screening, a pulptreatment process conventionally provides a refining step. To do thiseffectively the pulp consistency must be increased or be made moredense. Also, when pulp is placed in storage it is desirable to increasethe consistency to the maximum at which the material can be pumped.Thickening apparatus in accordance with the present invention would, insuch a pulp handling system, be arranged to receive screened and cleanedpulp, thicken it to a consistency of a selected density value and thendirect it to the refiners or to a storage chest in accordance with therequirements of the work, the supply to a refiner being in accordancewith the present inventive concept accomplished under pressure toincrease the refiner capacity and the versatility of its work.

The apparatus as disclosed is further capable, however, of handling awide variety of materials and so can be used advantageously inindustries other than paper pulp processing. Similarly it is not limitedto functioning as a pressure feeder in such systems but has generalapplication as a dewatering or low pressure washing means. In the latterinstance Water or other liquid is introduced and mixed with the pulpbefore its entry into the machine and is there drained with a consequentcarrying off ofunwanted solids from the pulp material.

Referring to the drawings, apparatus in accordance with the illustratedembodiment of the invention takes the form of a unitary machine forminga part of a continuous pulp treatment process, and being stationed toreceive watered pulp material, to place the material under pressure fora draining of excess liquid therefrom, and to de liver the dewatered orthickened pulp to a subsequent processing stage such as to a screw pressor to a refiner. As indicated in FIG. 1, the apparatus rests upon a support 10 and comprises power and working units 11 and 12 respectively.The former is mounted on a base 13 and includes a motor 14 which througha belt 15 and a gear reduction means 16 rotatably drives a shaft 17extending to the work performing unit 12. The latter is mounted on abase 18 which extends generally longitudinally of the support 1% and atright angles to the base 13. A housing 19 rests on the base 18 and hasits longitudinal axis parallel to and laterally offset from the shaft17. One end of the housing 19 faces the shaft 17 and receives acylindrical housing 21 closed at its outer end by a plate 22 providing abearing for the shaft 17'and also for one end of another shaft 23, thetwo shafts 23 and 17 or unitary continuations thereof extendinglongitudinally within the housing 19 in parallel spaced relation. On theshafts 17 and 23, within the housing cylinder 21, are meshing gears 24and 25 respectively. Op'er ation of the motor 14, therefore,results in apowered rotation of both shafts 17 and 23, with the direction ofrotation of the two shafts being counter to one another by virtue of thearrangement of gears 24 and 25. At their far ends the shafts 17 and 23extend through and beyond the housing19 and are suitably journaled in anadapter 26 secured to and projecting from the said opposite-end of thehousing 19. The adapter 26 interconnects the housing 19 and asupplemental housing 27 which extends generally at right angles to thehousing 19 to provide in effect a longitudinally extending passage 28which communicates through a transversely disposed relatively wideopening 29 with the outer end of the housing 19. Feed means in the formof a shaft 31 having a helicoid screw device 32 thereon islongitudinally disposed in the passage 23 for relative rotary motion.The shaft'31 extends through the rearward or closed end of the housing27 and is powered for independent rotation by means ineluding a motor33, a variable speed drive 364 and a driving connection 35. The helicoidsurface 32 projects substantially into contact with the walls of passage28 and so restricts or substantially precludes movement of materialthrough such passage except in conjunction with rotation of the feeddevice. The latter, in accordance with characteristics of devices ofthis kind, feeds or advances to the forward or open end of the passagematerial supplied to the helicoid surface through the laterally disposedopening 29.

The opening 29 in the supplemental housing 27 registers through theadapter 26 with a longitudinal extending flow passage 36 of reduceddiameter within housing 19. The passage 36 is defined by a cageextending between transversely disposed end plates 37 and 38 in thehousing 19. Such cage has a generally oval shape in order closely toenclose the shafts 17 and 21, these shafts having sleeves 39 and 41thereon respectively formed with helicoid sur faces 42 and 43, theperipheries of which approach a scraping contact with the cage. Thelatter comprises longitudinally extending laterally spaced apart wiresor rods 44 over which are placed transversely extending longitu dinallyspaced apart bars 45. The latter are wrapped around the exterior of therods 44 and are individually welded thereto to define and to maintain apredetermined spaced relation of the rods as well as maintaining aunitary relation between the rods and laterally extending bars. Acircular arrangement of wires 46 may be interposed between the rods 44and the bars 45 to interconnect one with the other.

Near to what may be considered its inner end, or that end adjacent tothe power unit 13, the housing 19 is formed with an inlet 47 disposed inthe processing system to receive the wet bulk material or the mixture ofliquid and solids. T he inlet 47 is located to introduce the materialfor treatment into the passage 36 at one end thereof and upon thesleeves 39 and 41 upon the shafts 1'7 and 23. The sleeves 39 and 41,together with the helicoid surfaces 43 and 42, make up a screw feedingdevice wherein the surfaces 42 and 43 constitute the flights of thescrews. ese flights have respectively opposite inclinations, and, sincethe direction of rotation of the shafts is counter to one another bothscrews rotate in a direction to advance the incoming material throughthe passage 36 toward the opposite end thereof. The twin screws are inparallel adjacent relation with the helicoid surfaces 42 and 43overlapping at their peripheries, or, in effect, interfitting. Inresponse to rotation of the screws, in the presence of admitted pulpmaterial, such material is picked up by the flights or helicoid surfacesof the screws and propelled in substantially a straight line withoutappreciable rotary movement with either of the screws. The overlappingof the helicoid surfaces provides interference zones wherein portions ofthe pulp are transferred from one surface to another, and, further, theoverlapping of such surfaces in effect reduces the space betweenadjacent flights of the screw means. Compression forces are generatedbetween adjacent flights in a manner tending to express fluids from thematerial. These fluids are permitted to drain through or to be expelledthrough the rods 44 of the surrounding cage. They find themselves, ineither event, in an annular space -48 between the housing 19 and cageand arethence communicated to the base 18 and suitably drawn oiftherefrom. The release of fluids from the advancing bulk material tendsto decrease the volume flow in the passage 36, while increasing thedensity of the material. To compensate therefor, and to maintain apressure upon the material throughout its travel through the passage 36,the helicoid surfaces or flights of the screws are constructed with adecreasing pitch, or constructed with a decrease in spacing betweenadjacent flights toward the outer end of the feeding device or in thedirection of movement of the material through the passage 36. Also, theflights of the screws are"made discontinuous, there being in theillustrated instance locations 49 and 51 upon each screw sleeve wherethe helicoid surface is interrupted. The result is to create at theselocations relatively wide spaces 52 and 53 between adjacentcorresponding flights of the screws. Material fed into these spacestends to form plugs creating zones of relatively elevated pressure inadvance thereof, it being understood, however, that the passage 36remains filled or substantially filled with the material under treatmentwhich is continuously in motion during operation of the screw feeddevices.

The screw feed mechanism operable in housing 19 continuously expels athickened material of increased density from the housing through theadapter 26. It is admitted to supplemental housing 27 through opening 29and there encounters the feed screw 3132. Restricted in its movement bysuch encounter, the material is progressively fed from the supplementalhousing through the passage 28 in response to rotation of the feed screwtherein and at a rate determined by the speed of operation of such feedscrew. The latter, as noted, being independently operated and controlledthrough a motor 33 and variable speed drive 34, is adapted to have itsspeed of operation varied independently of that of the main feed screwin housing 19 with the result that the back pressure created in passage36 by the feed screw 31-32 is variable.

Supplemental housing 27, along with the feed screw 3132, thereinaccordingly serves as a variable speed conveyor which is continuouslysupplied with thickened material from what may be considered the drainersection in housing 19. Held continuously under pressure, the material isforce fed through the drainer section, into the variable speed conveyorin housing 27 and from there delivered under conditions of continuingpressure to subsequent process equipment. The apparatus has beendisclosed as operating in a generally horizontal position, that is withits major axis parallel to the floor on which it rests. In view of theconstruction of the unitary machine, however, and in the light of itsconcept of pressure feeding, the machine may with suitable supportmodification be arranged in vertical and intermediate positions withoutmaterial affect upon its construction and mode of operation. Also, theback pressure in passage 36 may be varied by regulating the speed ofoperation of either one or both of the feed screw devices.

From the above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modification in its form, proportions,detail construction and arrangement of parts without departing from theprinciple involved or sacrificing any of its advantages While in orderto comply with the statute the invention has been described in languagemore or less specific as to structural features, it is to be understoodthat the invention is not limited to the specific features shown, butthat the means and construction herein disclosed comprise but one ofseveral modes of putting the invention into effect, and the invention istherefore claimed in any of its forms or modifications within thelegitimate and valid scope of the appended claims.

Having thus described our invention, we claim:

1. In the art of processing wet bulk material, apparatus to increase thedensity thereof including a cage having a drainer portion and atopposite ends thereof an inlet and an outlet for the wet bulk material,an outlet housing connected to said cage to receive the materialtherefrom through said outlet and having an outlet passage extendingangularly across said cage outlet, a screw feeding device in said cageoperable to advance admitted material from said inlet to said outlet,expressed fluid escaping by way of said drainer portion, and anotherscrew feeding device in said outlet housing longitudinally disposed insaid outlet passage to have material from said cage outlet depositedlaterally thereon, said last mentioned device restricting movement ofthe material issuing from said cage, and means for varying the backpressure in said cage in which the screw feeding device operates byvarying the speed of operation of said screw feeding device in saidoutlet housing.

2. In the art of processing wet bulk material, apparatus for the forcefeeding of such material, including first and second feed screw means inseries relation, said second means being arranged approximately at rightangles to the first said means with the said second screw meansextending transversely across the axis of the first screw means, housingmeans enclosing said second feed screw means, said housing meansproviding an inlet for the Wet bulk material for the feeding thereof bysaid first screw feed toward the said second screw means and furtherproviding a drainer section for the escape of fluids expressed from thematerial by said first screw feed means, said housing means extendinginto confining relation to the material as it moves from said firstscrew feed means to the second, said housing further providing an outletpassage for the material as it leaves said second screw feed means, andmeans for varying the back pressure in said housing means enclosing saidfirst screw feed means by varying the speed of operation of said secondscrew feed means.

3. In the art of processing wet bulk material, a thickening deviceincluding a main housing having an inlet and an outlet at opposite endsthereof, a supplemental housing receiving the bulk material from saidoutlet, said supplemental housing having an outlet offset from theoutlet from said main housing, main feed screw means in said mainhousing operable to advance admitted material from said inlet to saidoutlet and other feed screw means in said supplemental housing extendingacross the outlet of said main housing to receive material admittedtherefrom and advance it toward the outlet of said supplemental housing,said main housing being constructed for a permitted escape of fluidexpressed by said feed screw means therein, the said other feed screwmeans restricting movement of the material to the outlet in saidsupplemental housing, and means to vary the back pressure around saidmain feed screw means by varying the speed of the other screw means insaid supplemental housing.

4. A thickening and washing device according to claim 3, characterizedin that the said feed screw means in said main housing comprises twinscrews discharging material onto the said other feed screw means in saidsupplemental housing at longitudinally spaced points thereon.

References Cited in the file of this patent UNITED STATES PATENTS2,119,162 Hartner May 31, 1938 2,249,724 Anderson July 22, 19412,280,880 Anderson Apr. 28, 1942 FOREIGN PATENTS 461,388 Great BritainFeb. 16, 1937 18,365 Netherlands July 16, 1928 80,360 Norway June 23,1952

